In connection with performing jumping gymnastics from a floor, from a mat or on a trampoline, or similar elastic gymnastic appliance, the gymnast may either be suspended by two or four straps—typically elastic ropes when using a trampoline and otherwise in unyielding ropes—which are fixed either a distance above the gymnast or at least above the centre of gravity of the gymnast. For some of such specific gymnastic exercises, so-called twisting rings are used by which the gymnast is fixed in the twisting ring via a twisting belt or similar. Wearing this equipment the gymnast can perform jumps, and while the gymnast is in the air a large number of different exercises can be performed, including somersaults and twisting exercises by which the gymnast rotate about his/her transverse and longitudinal axes.
A twisting ring is typically made of metal, e.g. of aluminium, and includes an outer ring and an inner ring, and between these rings bearing balls or rollers are arranged. The inner one of the two rings can thus rotate in relation to the external ring about a common central axis, in principle as known from traditional ball bearings used for countless purposes in e.g. the mechanical industry. The common central axis in the twisting ring corresponds in principle to the longitudinal axis of a gymnast when he/she is situated in the twisting ring.
The outer ring typically includes fixing means in the form of eyelets or similar which are spaced apart about 180° at the outer periphery of the outer ring. These eyelets are used for fixing the mentioned elastic ropes—typically one or more—at each side.
At the periphery of the inner ring there is also arranged a number of fixing means/eyelets through which a wire, a rope or an elastic rope is drawn. Straps arranged at the external side of the twisting belt are then fixed to this rope.
The twisting belt causes the gymnast to be supported at least by a belt around the waist but frequently with belts/straps around each of the legs/thighs as well, such as known from climbing equipment and other types of safety belts. Twisting belts have, however, typically four straps along the external periphery through which the mentioned rope/wire is drawn. It is thus the length of the straps and the stiffness of the rope that determine the mutual adjusting options between twisting ring and twisting belt.
The number of these eyelets varies from twisting ring to twisting ring, and typically there are between 6 and 10 of such eyelets which are more or less evenly distributed along the periphery of the inner ring of the twisting ring.
Many eyelets on the inner ring provide that the twisting belt itself and thereby the gymnast can be centred better in the twisting ring, which is very important for optimal performance of the exercises. However, at the same time this will imply that the possibility of a good and optimal tightening/strapping of the twisting belt to the gymnast's body is poorer as the twisting belt is fixed relatively firmly at the centre of the twisting ring.
Few eyelets on the inner ring entail that the twisting belt and thereby the gymnast cannot easily be centred in the twisting ring, which is, as mentioned, very important for optimal performance of the exercises. However, fewer eyelets provide better possibility of a good and optimal tightening/strapping of the twisting belt to the gymnast's body as the twisting belt is more flexibly fixed to the twisting ring due to the fewer eyelets.
So, irrespectively whether there are many or few eyelets, there are thus some inexpediencies by the known solutions as either there is a good centrering of the twisting belt or a good tightening to the gymnast's body; both conditions are important but only one of the conditions can be achieved optimally. However, on some twisting rings this has been attempted solved, either by mounting steelwires or elastic ropes in the eyelets in order to optimise the possibility of a simultaneous good centrering of the gymnast and for a perfect tightening of the twisting belt to the body of the gymnast. Still, none of the prior art solutions are optimal as to allowing a gymnast to be centred together with optimal and individual tightening/strapping of the twisting belt to the body. Therefore it is typically necessary to acquire twisting rings as well as internally mounted twisting belts in different sizes where one of the accessible sizes in the one fitting the best—in the best case it fits well—but in far the most cases these twisting rings with permanently mounted twisting belts only fit tolerably.
Moreover, it is common to have two, three or more twisting rings with twisting belts in each size at one's disposal, typically three different sizes, such that a gymnast can put the equipment on and be ready for performing the exercise while another gymnast is already in action.
Such twisting rings with mounted twisting belts are relatively expensive, and it would therefore be very attractive to suffice with purchasing as few as possible and at the same time achieve a great flexibility during use such that e.g. a trampoline and the elastic ropes can be utilised optimally.
By the prior art products an optimal solution is not possible as there is a need for a large number of expensive twisting rings and as in many cases an optimal tightening of the twisting belt to the gymnast's body is not achieved.
An example of a gymnastic accessory for performing gymnastic exercises including a twisting ring with an external and internal ring that are concentrically connected is known from U.S. Pat. No. 2,496,748.